1. Field of Invention
The present invention relates to an LED illumination structure without a light guide plate (LGP), and more particularly to a side light LED illumination structure without the LGP capable of generating a uniform light emitting.
2. Description of Related Art
LEDs have the advantages of high illumination, power saving and long lifespan and will be the next start product in the lighting industry. Currently, the lighting LED illumination structure mainly includes a straight-down LED illumination structure, for example, the U.S. Pat. No. 7,819,542 entitled “Planar illumination light source device and planar illumination light device,” which mainly adopts a reflecting structure of a top diffusion sheet to realize the uniform light emitting.
Moreover, a side light LED illumination structure has been disclosed, for example, the ROC Patent No. 1341419 “backlight module,” which mainly adopts a light guide plate to guide light rays to an optical film like the diffusion sheet and then emit the light. Compared with the straight-down LED illumination structure, the side light LED illumination structure has the advantage of thin thickness and is adapted to serve as a large-scale illumination structure. However, this LED illumination structure is mainly used in the backlight module of an LCD display and has the defect of a heavy weight when used in the lighting facility.
The U.S. Pat. No. 5,453,855 entitled “Liquid crystal display device backlit by LED's coupled to printed circuit board,” the U.S. Pat. No. 6,966,684 entitled “Optical wave guide” or the ROC Patent No. 1318710 entitled “backlight module without LGP and diffusion plate” are directed to overcome the defects of the side light LED illumination structure. In the aforementioned patents, the light guide plate is omitted and a particular reflecting structure of a reflecting bottom plate is employed for reflecting the light rays to form a uniform light emitting surface.
However, either the straight-down LED illumination structure or the side light LED illumination structure in any forms is still in need of improvement of the light emitting uniformity of the light emitting surface.
Additionally, with the progress of the 3D image technology, the bare-eyed 3D image is the key technology under development by the researchers. However, the bare-eyed 3D image technology is disadvantageous in the control of the light projection of the illumination structure. An illumination structure adapted for the bare-eyed 3D image technology has been disclosed in the U.S. Pat. No. 7,750,982 entitled “Autostereoscopic display with fresnel lens element and double sided prism film adjacent a backlight having a light transmission surface with left and right eye light sources at opposing ends modulated at a rate of at least 90 Hz.” However, the illumination structure still needs the light guide plate for guiding the emitting of the light rays, so this illumination structure also has the defects of a heavy weight and a large thickness.